Variometer



May 31, 1932.

w. DUBILIER 1,861,052

vAmoMETER Filed Sept. 8. 1926 l'l zo m /9 INVENT:

DY william ubl'lier WMSM HTTORPIEY Patented May 31, 1932 UNITED STATES Parar Fris WILLIAM DUBILIER, OF NEW ROCHELLE, NEW YORK, ASSIGNOR TO DUBILIFR CON- DENSER CORPORATION, OF N EV YORK, N. Y., A CORPORATION 0F DELAWARE VARIOMETER Application filed September 8, 1926.

This invention relates to controlling devices; and especially controlling devices for the circuits of radio receiving appliances.

An object of the invention is to provide a means and method for controlling the tuning of a multi-stage radio receiver over a very wide range, and with a comparatively small quantity of apparatus, and material for constructing same.

The. nature of the invention is set forth in the following description, and the novel features pointed out in the appended claims. But this disclosure is by way of example only and I may vary the construction within permissible limits, without departing from the principle of the invention.

On the drawings:

Figure 1 shows a radio receiving set according to my invention;

Figure 2 is a side view;

Figure 3 is a crass section; and

Figure 4 is a bottom plan of a variometer device which is a part of such a set; and

Figures 5 and 6 show in top plan two modified forms of the invention.

The same numerals identify the same parts throughout.

In practice I make use in a radio set of a novel form of variometer, shown particularly in Figures 2, 3 and 4, comprising a support 1 of insulation shown as cylindrical in form. Around the exterior of this support is wrapped a coil of wire 2 which is without an insulation covering and one. end of this coil 2 is connected toa terminal 3 having a binding screw 4 to enable a conductor to be secured to the terminal. Through the support 1 extends an axial shaft 5 mounted to turn in a bearing 6 and affixed to one end of the shaft is a knob 7 to be grasped by the operator. Also atlixed to support 1 is another terminal 8 having a binding screw 4, this terminal making contact with the shaft 5 which is, of course, of metal. The shaft carries an arm 9, provided with a sliding contact 10 to engage the turns of the coil 2 at various points, and thus the circuit will be from the terminal 3 through the turns of the coil 2 to the brush 10, arm 9, shaft 5, and terminal 8.

Serial No. 134,293.

The number of turns of the coil 2 in circuit can be varied down to a very small portion of one rotation and when the device is used in a radio receiving set, a very wide tuning range is afforded. Since a large capacity may be used with a very low power factor, the efficiency of suc-h a receiving set will be high. l/Vith the usual receiving' set, the capacit-y for tuning purposes is of the order of 250 to 500 cms., while the inductance of either the fixed or the vario-meter coils is of the order of 50,000 to 300,000 cms. I-Ience, a large quantity of wire is required and considerable losses are sustained.

This invention contemplates a capacity of the order of 5,000 to 20,000 cms., while the inductance may be of the order of 20,000 to 2,000 cms. I-Ience, much less wire is needed -and much lower losses ensue.

In general, the ratio of the inductance to capacity in this invention will be less than 5, while in the usual type of radio receiving set, the same ratio has been greater than 100.

In Figure 1, I illustrate a receiving set in which the principle of my invention is embodied. This view indicates at 11 an aerial grounded at 12 and comprising a coil 13. In inductive relation to this coil 13, I put one of my above described variometer coils 2 arranged in parallel with a condenser 111.

Inductively related to the coil 2 is a coil 15 connected at one end to the grid of a vacuum tube T1, and at the other end to a wire 16 joined to one terminal of a filament battery A. The anode of this tube is connected to one terminal of a primary winding 17, the other end being united to a conductor 13 which leads from one terminal to an anode battery B, the other terminal of this battery being joined to the battery A opposite the point t-o which the aforesaid wire 16 is connected.

Inductively related to the coil 17 is another variometer coil 2 in parallel with a condenser 14, and inductively related to this coil 2 is another secondary 15 united at one end to the grid of a tube T2 and at the other end to aforesaid wire 16. The anode of this tube I2 is connected to a similar primary 17 which is also joined to the wire 18, and inductively related to this primary 17 is another coil 2 joined to a condenser 14 in position to affect inductively a third secondary coil 15 united to the grid of the third tube T3. The connection between the one terminal of this third coil 15 and the tube T3 includes a grid leak resistance 19 and condenser 20, and the other terminal of this coil is joined to wire 18. The anode of tube T3 is connected to one end of the primary 2l of an iron core transformer, the opposite terminal of which connects to a battery 22 united to the filament of this tube. The secondary 23 associated with the primary 21 is joined to the aforesaid Wire 1G and to the grid of the last tube Tg. The anode of this tube T4 is joined to a sound reproducing device S to which the Wire 18 also leads. From between the batteries A and B extends another wire 1G, the filaments of the four tubes 25 being bridged across these two wires so as to be heated from the battery A.

In practice such a set can be made up as indicated in Figure 5 where 26 is the base and 27 the panel and Q8 the sockets for the tubes, there being an extra socket for the fifth tube if desired.

The three variometers are arranged so that their arms 9 can be operated in unison and for this` purpose their arms are all carried upon a common shaft 29 extending through all of the supports l. Each of these supports may be mounted in a suitable upright resting upon the base 26. At one end of the shaft 29 is a pinion 81 meshing with a pinion 32 which is fixed to a sha t 33 having a bearing in the panel 27 and having an operating knob 34. To avoid one of the coils :2 influencing any of the others, shields 35 shown in edge view from the top may be placed on the base 26 between the various coils 2. The numeral 36 indicates a socket for a jack and 37 additional appliances which may be included in the make-up of this set.

Figure 6 indicates a construction similar to Figure 5, except that the arms 9 of the coils 2 instead of being mounted on the same shaft are provided with separate shafts, the ends of which are joined by flexible connections 38. The supports l and the uprights SO for carrying same are so disposed on the base 26 that the axis of the first coil 2 is perpendicular to the axis of the second coil Q.

The axis of the third coil is perpendicular to the axis of the other two and thus the coils could have no cross inductive effect and no shielding is needed.

Having described my invention, what I believe to be new and desire to secure and protect by Letters Patent of the United States is:

1. The combination With a radio receiving set having appliances for detecting and amplifying oscillations, of a plurality of devices for controlling said appliances, said devices khaving the form of coils, with means for varying the effective number of turns thereof, all of said coils being mounted so that said means can be operated in unison, said coils being disposed so that the axis of each is perpendicular to the axis of all the rest.

2. In a radio receiving set having circuits for detecting and amplifying oscillations, a plurality of variable tuning coils for controlling said circuits, the axis of each of the tuning' coils being disposed at an angle to the axis of an adjacent coil in such manner as to Shield the coils, and driving connections extending between the axes of the respective tuning coils to actuate the coils simultaneously with movement of any one of them.

3. In a radio receiving set having appliances for detecting and amplifying oscillations, a plurality of tuning coils for controlling the circuits, means for varying the ef` fective number of turns of each of the coils, the axis of each of the coils being disposed at an angle to the axis of each of the adjacent coils, and means for causing all of said coils to operate in unison, said means comprising flexible connections between the coils.

4. In a radio receiving set having circuits for detecting and amplifying oscillations, a plurality of variable tuning coils for` controliing said circuits, the axis of each of the tuning coils being perpendicular to the axes of the adjacent coils to shield the coils from each other, and a unitary control means for all of said coils comprising flexible driving connections extending between the axes of the re` spective coils.

In testimony whereof I afix my signature.

WILLIAM DUBILIER. 

